DOUBLE-NEEDLE IRIS SUTURE FIXATION FOR DISLOCATED IOLS
John C. Hart Jr, MD
McCannel described the first technique for suture fixation of an intraocular lens (IOL) to the iris in 1976.1 The McCannel suture technique requires corneal paracenteses overlying the knots to externalize the sutures. Stark and coauthors described iris fixation of posteriorly dislocated IOLs using the McCannel suture technique in 1980.2 Siepser published his innovative slip knot technique in 1994.3 The advantage of this suture technique is that it allowed knot tying within a closed anterior chamber and did not require additional paracenteses. Condon4 and later Chang5 employed the Siepser technique when fixating IOLs to the iris. These techniques all use a single suture needle pass to fixate the haptics of an IOL to the iris. Although these techniques are extremely useful for IOL fixation, the iris and pupil are often left distorted (Figure 28-1).
In contrast, with the double-needle iris/IOL fixation technique a suture needle serves as a third “hand” within the anterior chamber to lift and stretch the peripheral iris prior to haptic suture fixation with a second needle pass. This technique allows the surgeon to support the IOL haptic with suture bites that are smaller and more peripherally positioned through the iris in order to minimize iris and pupillary distortion. Suture fixation of a dislocated IOL is primarily reserved for IOLs that are not within the capsular bag and are of a 3-piece design. Iris fixation of single-piece polymethylmethacrylate IOLs is possible but technically more difficult, particularly if the IOL is planar in design.
Description of the Technique
Prior to fixation of a 3-piece IOL to the iris, the surgeon must assess the status of the vitreous in relation to the dislocated IOL. To prevent vitreous traction, appropriate limbal or pars plana anterior vitrectomy should be performed if there is vitreous in the anterior segment or adherent to the IOL.
For any dislocated IOL it is critical to assess its position within the eye. If the IOL is in the anterior vitreous or on the pars plana, a posterior-assisted levitation (PAL) technique6 may be necessary to bring the IOL into the anterior chamber. It is also critical to determine whether the IOL is oriented right side up (Figure 28-2). If the IOL is inverted, it should be flipped so that it is right side up prior to iris fixation (Video 28-1). This maneuver should be performed after appropriate anterior vitrectomy has removed any vitreous entangled with the IOL. For dislocated IOLs located within the capsular bag or ciliary sulcus, an anterior approach using instrumentation through 2 paracenteses is sufficient to deliver the optic anterior to the pupillary plane.
Assuming a temporal main incision, 1-mm paracenteses are created at the superior-temporal and inferior-temporal limbus. A miotic agent (Miochol [acetylcholine chloride) is injected into the anterior chamber. After miosis of the pupil, a dispersive ophthalmic viscosurgical device (OVD) is instilled into the anterior chamber. The optic of the IOL is visualized by retracting the iris with a Kuglen hook. A 27-gauge OVD cannula is then passed through the pupil and then beneath the optic of the IOL. The optic is then elevated anteriorly through the pupil with the 27-gauge cannula. The iris is displaced off the opposite side of the optic with a Kuglen hook. This maneuver captures the optic anterior to the iris while the haptics remain posterior to it (Video 28-2). Care is taken to ensure that equal amounts of iris are distributed between the 2 haptics. An oblique paracentesis is created approximately 90 degrees away from where the haptic shaft is located beneath the iris. Proper placement of this paracentesis is best visualized by drawing an imaginary line parallel to the haptic (Figure 28-3). The internal opening of the paracentesis should touch this imaginary line. A 10-0 Prolene (Ethicon) suture double armed with CTC-6L needles (Ethicon) is recommended for this technique. One needle is cut free and is passed via the oblique paracentesis down through the peripheral iris on one side of the haptic, and then back up through the iris stroma on the other side of the haptic. This initial needle pass captures the underlying haptic (Figure 28-4). The needle tip is then swept away from the iris root and then driven externally through the peripheral cornea (Figure 28-5). This maneuver achieves 4 important objectives. It decreases the angle between the iris and the cornea, stretches the iris away from the iris root, fixates the stretched iris to the cornea, and drapes the iris over the haptic highlighting the area for subsequent suture fixation. The second CTC-6L needle with 10-0 Prolene suture attached is then passed through the same oblique entry paracentesis, but posterior to the first needle. Since the iris has been placed on stretch by the first needle, and more of the peripheral iris is visible, and the second needle can be passed more peripherally into the iris for haptic fixation. Keeping the peripheral iris under tension allows the second needle to take a smaller, more controlled bite of iris tissue. The bite of iris tissue should be taken as perpendicular to the underlying haptic as possible (Figure 28-6). Both needles are then removed from the eye leaving the Prolene suture beneath the haptic. The same suturing technique is repeated for the opposite haptic. Both sutures are tied with a double overhand knot using the Siepser sliding knot technique.3 It is important to not complete or lock the knots at this point. The optic of the IOL is then prolapsed posteriorly through the pupil, which permits evaluation of any iris or pupil distortion caused by the sutures. Because the sutures have not yet been locked, if any iris or pupillary distortion is observed, incarcerated iris tissue can be mobilized out of the knots by pulling on the pupil margin with micrograspers. If this maneuver does not resolve the pupil distortion, then the suture could be removed so that the double-needle iris/IOL suture fixation technique may be repeated for that haptic. Once any incarcerated iris tissue has been released, the knots are then locked with 2 single overhand knots using the Siepser sliding knot technique (Video 28-3).
Figure 28-1. Iris and pupil distortion commonly seen with suture fixation of an IOL to the iris.
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